Abrasive article and method of making same

Abstract

An abrasive article is presented that includes a backing, a primer coating applied on the backing, and a plurality of shaped abrasive particles embedded in the primer coating. The coating weight of the plurality of shaped abrasive particles is greater than 300 particles per square inch. In accordance with grinding test 4, the abrasive article exhibits a GT4 Total Cutting LP of at least 390 grams, a GT4 Total Cutting MP of at least 860 grams, and a GT4 Total Cutting HP of at least 1300 grams when used to grind a substrate.

Description

Background Art

[0001] Abrasive grains and abrasive articles comprising abrasive grains can be used to grind, polish or grind a variety of materials and surfaces during product manufacturing.Therefore, there is always a need to improve the cost, performance or life of abrasive grains or abrasive articles. Summary of the Invention

[0002] An abrasive article is provided, comprising a backing, a make coat applied to the backing, and a plurality of shaped abrasive particles embedded in the make coat. The plurality of shaped abrasive particles has a coating weight greater than 300 particles per square inch. According to Grinding Test 4, the abrasive article exhibits a GT4 Total Cut LP of at least 390 grams, a GT4 Total Cut MP of at least 860 grams, and a GT4 Total Cut HP of at least 1300 grams when used to abrade a substrate.

[0003] Shaped abrasive particles can often offer superior performance to randomly crushed abrasive particles. However, there are common expectations regarding how shaped abrasive particles of varying coat weights will perform under varying applied pressures. Generally speaking, the higher the coat weight, the lower the expected performance at low or medium pressures, as the pressure is distributed across a greater number of particle tips, and the tips don't break off and create new sharp tips. Conversely, low coat weight tapes are not expected to perform well at high pressures, as the unit pressure per tip is too high and the particles break off and fragment too quickly.

[0004] Surprisingly, a construction has been discovered that performs well over a wide range of pressures and over an even wider range of coating weights. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1A to Figure 1B is a schematic perspective view of shaped abrasive particles that can be used in exemplary articles described herein.

[0006] Figures 2A-1 to 2D-2 Different shaped abrasive particles that can be used to form abrasive articles are shown.

[0007] Figure 3 Methods of forming abrasive articles according to embodiments herein are shown.

[0008] Figure 4 A cross-sectional view of an exemplary abrasive article according to embodiments herein is shown.

[0009] Figures 5A to 5C Example thickness measurements of the abrasive particles herein are shown.

[0010] Figures 6A to 6B Example side length measurements of the abrasive particles herein are shown.

[0011] Figures 7 to 11 The grinding data described in detail in the examples are shown.

[0012] Although the above-described drawings illustrate several embodiments of the present disclosure, other embodiments are also contemplated, for example, as noted in the discussion. In all cases, the present disclosure is presented by way of example and not limitation. It will be appreciated that those skilled in the art can devise numerous other modifications and embodiments that fall within the scope and spirit of the principles of the present disclosure. The accompanying drawings may not be drawn to scale. Like reference numerals may be used to represent like parts throughout the drawings. DETAILED DESCRIPTION

[0013] The following definitions apply throughout the specification and claims.

[0014] The term "aspect ratio" refers to the side length (as defined herein) divided by the thickness (as defined herein). To determine the aspect ratio of shaped abrasive particles according to the present specification, the thickness and side length measurements of the same 20 randomly selected shaped abrasive particles (see below) are used.

[0015] The term "length" refers to the maximum extent of an object along its largest dimension.

[0016] The term "width" refers to the maximum extent of something along the dimension orthogonal to its length.

[0017] The term "thickness" refers to the greatest extent of something along a dimension orthogonal to both length and width. To determine the thickness of shaped abrasive particles according to the present specification, 20 shaped abrasive particles are randomly selected from a larger batch of similar particles, and three thickness measurements (T1, T2, and T3) are taken for each of the 20 particles at the following locations along the sidewall: (i) each end of the sidewall; and (ii) the center of the sidewall (e.g., Figures 5A to 5C The resulting 60 individual thickness measurements were then averaged to determine the thickness of the shaped abrasive particles.

[0018] The term "major surface" refers to a surface that is larger than at least half of the surface of the object in question.

[0019] The term "perimeter" refers to the closed boundary of a surface, which may be a flat surface or a non-flat surface.

[0020] The term "precisely shaped" means that the shape is replicated from a mold cavity used during the manufacture of the ceramic abrasive particles. The term "precisely shaped" excludes random shapes obtained by mechanical comminution operations or explosive comminution.

[0021] The term "side length" refers to the straight-line distance from tip to tip of a shaped abrasive particle along one of its side walls (e.g., Figures 5A to 6BTo determine the side length of shaped abrasive particles according to the present specification, 20 shaped abrasive particles are randomly selected from a larger batch of similar particles, and the side length of each of the 20 particles is measured along the side wall. The 20 individual side length measurements are then averaged to determine the side length of the shaped abrasive particles.

[0022] The features and advantages of the present invention will be further understood by considering the detailed description and the appended claims.

[0023] Figure 1A to Figure 1B is a schematic perspective view of exemplary shaped abrasive particles that can be used in abrasive articles according to the present disclosure. Figure 1A Particles of the shape shown are described in more detail in U.S. Patent No. 10,301,518 B2, issued May 28, 2019, which is incorporated herein by reference (e.g., see Figure 3 to Figure 5 and related description). Figure 1B Particles of the shape shown are described in more detail in published PCT application WO 2021 / 245492 (Liu et al.), published on December 9, 2021 (see, e.g., Figures 6A to 6B and related descriptions, which are incorporated herein by reference) and published PCT application No. WO 2021 / 245494 (Liu et al.), published on December 9, 2021 (see, e.g., Figure 4 A to Figure 4 B and related descriptions, incorporated herein by reference). Reference is now made to Figure 1A Exemplary shaped ceramic abrasive particle 1 includes a first surface 10 having a perimeter 20. Perimeter 20 includes a first edge 30, a second edge 32, and a third edge 34. First edge 30 is a concave monotonic curve, while second edge 32 and third edge 34 are substantially straight edges. However, it is expressly contemplated that in some embodiments, second edge and / or third edge, or all three edges, may be concave monotonic curves. Second surface 70 is opposite first major surface 10 and does not contact the first major surface. Peripheral surface 80 has a predetermined shape and is disposed between and connects first and second surfaces 10 and 70. Peripheral surface 80 includes a first wall 82, a second wall 84, and a third wall 86. First edge 30, second edge 32, and third edge 34 represent the intersection of first wall 82, second wall 84, and third wall 86, respectively, with perimeter 20. The first region 90 of the perimeter 20 includes the first edge 30 extending inwardly and terminating at the first corner 50 and the second corner 52 , thereby defining respective first and second acute interior angles 60 , 62 .

[0024] like Figure 1AAs shown, the first region of the perimeter may include a single curved inwardly extending edge, however, it is also contemplated that the first region of the perimeter may include multiple edges (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, or more edges), any or all of which may include an inwardly extending curvature.

[0025] The term "draft angle" refers to the angle of the taper that is incorporated into the wall of the mold cavity so that the opening of the mold cavity is wider than its base. The draft angle can be varied to change the relative sizes of the first and second surfaces and the sides of the circumferential surface. In various embodiments of the present disclosure, the draft angle μ can be 90 degrees, or in the range of about 95 degrees to about 130 degrees, about 95 degrees to about 125 degrees, about 95 degrees to about 120 degrees, about 95 degrees to about 115 degrees, about 95 degrees to about 110 degrees, about 95 degrees to about 105 degrees, or about 95 degrees to about 100 degrees. As used herein, the term draft angle also refers to the taper angle of the wall of the molded body that corresponds to the draft angle of the mold used to prepare the molded body. For example, Figure 1A The draft angle of the exemplary shaped ceramic abrasive particle 1 in φ ...

[0026] It should be noted that, as discussed herein, the manufacturing process can introduce variations and changes to the final particle specifications. For example, the final draft angle, side length, aspect ratio, and thickness can generally fall within expected ranges.

[0027] In some embodiments, the inwardly extending regions of shaped ceramic abrasive particles according to the present disclosure can have a maximum depth that is at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or even 60% of the largest dimension of the shaped ceramic abrasive particles parallel to the maximum depth. Figure 1A , the maximum dimension 18 is parallel to the maximum depth 15 .

[0028] Figure 1B Shows something like Figure 1A Another shaped abrasive particle. Particle 100 has a first surface 102, the first surface and the second surface 104 separated by a certain thickness 106. Figure 1B As shown, surfaces 102 and 104 may each have a curvature and be separated by a substantially constant thickness such that surfaces 102 and 104 may be considered parallel, curved, planar surfaces. Figure 1BAs shown, the curvature of surfaces 102 and 104 can be used to produce an edge (e.g., edge 112) that is more stable in an upright position. As described herein, the upright orientation includes a tip 114 that is opposite to backing 108. However, it is expressly contemplated that particles 100 can be angled relative to backing 108, as shown by angle 110. In some embodiments, angling a majority of shaped abrasive particles 100 on the backing surface can result in an abrasive article having a first cutting rate in a first direction and a second cutting rate in a second direction. This is due to the fact that if the shaped abrasive particles 100 are pulled against a surface facing forward against a concave surface (e.g., face 104), the shaped abrasive particles resemble a shovel, thereby cutting out a greater amount of material from the substrate than when facing such that surface 102 faces forward.

[0029] Typically, the precisely shaped abrasive particles according to the present disclosure have a thickness that is significantly less than their length and / or width, but this is not required. For example, the thickness of the shaped ceramic abrasive particles can be less than or equal to one-third, one-fifth, or one-tenth of their length and / or width.

[0030] Generally, the first and second surfaces are substantially parallel, or more parallel; however, this is not required. For example, random deviations due to drying may cause one or both of the first and second major surfaces to be uneven. Similarly, the first and / or second major surfaces may have parallel grooves formed therein, for example, as described in U.S. Patent Application Publication No. 2010 / 0146867A1 (Boden et al.).

[0031] The shaped ceramic abrasive particles according to the present disclosure comprise a ceramic material. In some embodiments, they may consist essentially of or even consist of a ceramic material, but they may contain a non-ceramic phase (e.g., as in glass-ceramics). Examples of suitable ceramic materials include alpha alumina, fused alumina-zirconia, and fused oxynitride. Additional details about sol-gel derived ceramic materials suitable for use in the shaped ceramic abrasive particles according to the present disclosure can be found, for example, in U.S. Patent No. 4,314,827 (Leitheiser et al.), U.S. Patent No. 4,518,397 (Leitheiser et al.); U.S. Patent No. 4,623,364 (Cottringer et al.); U.S. Patent No. 4,744,802 (Schwabel); U.S. Patent No. 4,770,671 (Monroe et al.); U.S. Patent No. 4,881,951 (Wood et al.); U.S. Patent No. 4,960,441 (Pel low et al.); U.S. Patent No. 5,139,978 (Wood); U.S. Patent No. 5,201,916 (Berg et al.); U.S. Patent No. 5,366,523 (Rowenhorst et al.); U.S. Patent No. 5,429,647 (Larmie); U.S. Patent No. 5,547,479 (Conwell et al.); U.S. Patent No. 5,498,269 (Larmie); U.S. Patent No. 5,551,963 (Larmie); U.S. Patent No. 5,725,162 (Garg et al.) and U.S. Patent No. 6,054,093 (Torre et al.).

[0032] Shaped ceramic abrasive particles according to the present disclosure are typically used as a plurality of particles that can include the shaped ceramic abrasive particles of the present disclosure, other shaped abrasive particles, and / or crushed abrasive particles. For example, a plurality of abrasive particles according to the present disclosure can include, by value, at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or even 99% or more of the shaped ceramic abrasive particles described herein. The shaped ceramic abrasive particles can have the same nominal size and shape, but in some embodiments, it can be useful to use a combination of sizes and / or shapes.

[0033] Typically, shaped ceramic abrasive particles according to the present disclosure have a relatively small maximum particle dimension; for example, less than about 1 centimeter (cm), 5 millimeters (mm), 2 mm, 1 mm, 200 microns, 100 microns, 50 microns, 20 microns, 10 microns, or even less than 5 microns, although other sizes can also be used.

[0034] Any abrasive particles mentioned in this disclosure may be sized according to nominal grades recognized and specified by the abrasive industry. Exemplary abrasive industry recognized grading standards include those promulgated by ANSI (American National Standards Institute), FEPA (European Abrasive Manufacturers Federation), and JIS (Japanese Industrial Standards). Such industry-recognized grading standards include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 30, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI320, ANSI 360, ANSI 400, and ANSI 600; FEPA P8, FEPA P12, FEPA P16, FEPA P24, FEPA P30, FEPA P36, FEPA P40, FEPA P50, FEPA P60, FEPA P80, FEPA P100, FEPA P120, FEPA P150, FEPA P180, FEPA P220, FEPA P320, FEPA P400, FEPA P500, FEPA P600, FEPA P800, FEPAP1000, and FEPA P1200; and JIS 8, JIS12, JIS 16, JIS24, JIS 36, JIS 46, JIS 54, JIS 60, JIS 80, JIS100, JIS150, JIS 180, JIS220, JIS240, JIS280, JIS 320, JIS 360, JIS 400, JIS400, JIS 600, JIS 800, JIS1000, JIS1500, JIS2500, JIS 4000, JIS 6000, JIS 8000 and JIS10,000. More typically, the shaped ceramic abrasive particles are individually sized according to ANSI 60 and 80 or FEPA P60 and P80 grading standards.

[0035] The term "abrasive industry recognized specified nominal grade" also includes abrasive industry recognized specified nominal screening grade. For example, the specified nominal screening grade may be graded as a nominal screening grade using U.S. Standard Test Sieve Meshes conforming to ASTM E-11-09 "Standard Specification for Wire Cloth and Sieves for Testing Purposes." ASTM E-11-09 sets forth the design and construction requirements for test sieves that utilize a woven wire cloth media mounted in a frame to classify materials according to a specified particle size. A typical designation may be expressed as -18+20, meaning that the shaped ceramic abrasive particles pass through a test sieve conforming to the specifications of ASTM E11-09 "Standard Specification for Wire Cloth and Sieves for Testing Purposes" for a No. 18 sieve and are retained on a test sieve conforming to the specifications of ASTM E11-09 for a No. 20 sieve. In one embodiment, the shaped ceramic abrasive particles have a particle size such that at least 90% of the particles pass through an 18 mesh test sieve and can be retained on a 20 mesh, 25 mesh, 30 mesh, 35 mesh, 40 mesh, 45 mesh, or 50 mesh test sieve. In various embodiments, the shaped ceramic abrasive particles can have a nominal screen grade including: -18+20, -20+25, -25+30, -30+35, -35+40, -40+45, -45+50, -50+60, -60+70, -70+80, -80+100, -100+120, -120+140, -140+170, -170+200, -200+230, -230+270, -270+325, -325+400, -400+450, -450+500, or -500+635.

[0036] In some embodiments, shaped ceramic abrasive particles can be made according to a multi-step process. The process can be performed using a ceramic precursor dispersion (e.g., a dispersion (e.g., a sol-gel) containing ceramic precursor materials.

[0037] Briefly, the method includes the steps of making a seeded or unseeded ceramic precursor dispersion that can be converted to a corresponding ceramic (e.g., a boehmite sol-gel that can be converted to alpha alumina); filling one or more mold cavities having the desired outer shape of shaped abrasive particles with the ceramic precursor dispersion, drying the ceramic precursor dispersion to form shaped ceramic precursor particles; removing the shaped ceramic precursor particles from the mold cavities; calcining the shaped ceramic precursor particles to form calcined shaped ceramic precursor particles, and then sintering the calcined shaped ceramic precursor particles to form shaped ceramic abrasive particles.

[0038] In some embodiments, the calcining step is omitted and the shaped ceramic precursor particles are sintered directly after being removed from the mold. In some embodiments, the mold can be made of a sacrificial material (e.g., a polyolefin material) that burns out during calcining or sintering, thereby eliminating the need to separate the ceramic precursor particles from the mold during processing.

[0039] The process will now be described in more detail in the context of shaped ceramic abrasive particles containing alpha-alumina.

[0040] The first process step involves providing a seeded or unseeded dispersion of a ceramic precursor material (i.e., a ceramic precursor dispersion) that can be converted into a ceramic material. Ceramic precursor dispersions often contain a volatile liquid component. In one embodiment, the volatile liquid component is water. The ceramic precursor dispersion should contain enough liquid to make the viscosity of the dispersion low enough to fill the mold cavity and replicate the mold surface, but the amount of liquid should not be too much so that the cost of subsequently removing the liquid from the mold cavity is too high. In one embodiment, the ceramic precursor dispersion contains 2% to 90% by weight of particles that can be converted into ceramics (such as particles of aluminum oxide monohydrate (boehmite) or another aluminum oxide precursor), and at least 10% to 98% by weight, or 50% to 70% by weight, or 50% to 60% by weight of a volatile component (such as water). Conversely, in some embodiments, the ceramic precursor dispersion contains 30% to 50% by weight, or 40% to 50% by weight of solids.

[0041] Examples of useful ceramic precursor dispersions include zirconium oxide sols, vanadium oxide sols, ceria sols, aluminum oxide sols, and combinations thereof. Useful aluminum oxide dispersions include, for example, boehmite dispersions and other aluminum oxide hydrate dispersions. Boehmite can be prepared by known techniques or can be commercially obtained. Examples of commercially available boehmite include products sold under the trade names "DISPERAL" and "DISPAL," both from Sasol North America, Inc., or under the trade name "HIQ-40," from BASF. These monohydrated aluminum oxides are relatively pure; that is, they contain relatively little, if any, other hydrate phases besides the monohydrate and have a high surface area.

[0042] Other examples of suitable ceramic precursor materials include non-colloidal alumina slurries as described in U.S. Patent No. 10,400,146 (Rosenflanz et al.), issued September 3, 2019.

[0043] The physical properties of the resulting shaped ceramic abrasive particles will generally depend on the types of materials used in the ceramic precursor dispersion.As used herein, a "gel" is a three-dimensional network of solids dispersed in a liquid.

[0044] The ceramic precursor dispersion may contain modifying additives or precursors of modifying additives. Modifying additives can be used to enhance certain desired properties of the abrasive particles or to improve the efficiency of subsequent sintering steps. Modifying additives or precursors of modifying additives can be in the form of soluble salts, typically water-soluble salts. They are typically composed of metal-containing compounds and can be precursors of oxides of the following substances: magnesium, zinc, iron, silicon, cobalt, nickel, zirconium, hafnium, chromium, yttrium, praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, titanium, and mixtures thereof. The specific concentrations of these additives that can be present in the ceramic precursor dispersion can be adjusted by those skilled in the art.

[0045] Typically, the introduction of a modifying additive or a modifying additive precursor will cause the ceramic precursor dispersion to gel. The ceramic precursor dispersion can also be gelled by heating it for a period of time to reduce the liquid content of the dispersion by evaporation. The ceramic precursor dispersion can also contain a nucleating agent. Nucleating agents suitable for use in the present disclosure can include fine particles of alpha alumina, alpha iron oxide or its precursors, titanium dioxide and titanates, chromium oxide, or any other substance that nucleates the conversion. If a nucleating agent is used, the amount should be sufficient to convert the alpha-alumina. Methods for nucleating alpha alumina precursor dispersions are disclosed in U.S. Patent No. 4,744,802 (Schwabel).

[0046] Peptizing agents can be added to the ceramic precursor dispersion to produce a more stable hydrosol or colloidal ceramic precursor dispersion. Suitable peptizing agents are monoprotic acids or acidic compounds such as acetic acid, hydrochloric acid, formic acid and nitric acid. Polyprotic acids can also be used, but they may cause the ceramic precursor dispersion to gel rapidly, making it difficult to treat or introduce additional components thereto. Some commercially available boehmite contains an acid titer (such as absorbed formic acid or nitric acid) that helps form a stable ceramic precursor dispersion.

[0047] The ceramic precursor dispersion can be formed by any suitable means; for example, in the case of a sol-gel alumina precursor, simply mixing alumina monohydrate with water containing a peptizing agent, or forming a slurry of alumina monohydrate to which a peptizing agent is added.

[0048] Defoamers or other suitable chemicals may be added to reduce the tendency to form bubbles or entrap air during mixing. Other chemicals such as wetting agents, alcohols, or coupling agents may be added if desired.

[0049] The second process step involves providing a mold having at least one mold cavity, and preferably a plurality of cavities, formed in at least one major surface of the mold.

[0050] In some embodiments, the mold is formed as a production tool, which can be, for example, a belt, a sheet, a continuous fiber web, a coating roller such as a rotary gravure roller, a sleeve mounted on a coating roller, or a die. In one embodiment, the production tool comprises a polymeric material. Examples of suitable polymeric materials include thermoplastics such as polyesters, polycarbonates, poly(ethersulfone), poly(methyl methacrylate), polyurethanes, polyvinyl chloride, polyolefins, polystyrene, polypropylene, polyethylene, or combinations thereof, or thermosetting materials. In one embodiment, the entire mold is made of a polymeric material or a thermoplastic material. In another embodiment, the surface of the mold that contacts the ceramic precursor dispersion during drying (such as the surface of multiple cavities) comprises a polymeric material or a thermoplastic material, and the other parts of the mold can be made of other materials. By way of example, a suitable polymer coating can be applied to a metal mold to change its surface tension properties.

[0051] Polymer or thermoplastic production tools can be replicated from a metal master tool. The master tool will have the reverse pattern desired for the production tool. The master tool can be made in the same manner as the production tool. In one embodiment, the master tool is made of a metal, such as nickel, and is diamond turned. In one embodiment, the master tool is formed at least in part using a stereolithography technique. The polymer sheet material can be heated together with the master tool so that the master tool pattern is embossed on the polymer material by pressing the two together. Alternatively, a polymer or thermoplastic material can be extruded or cast onto the master tool and then pressed. The thermoplastic material is cooled to harden, thereby producing the production tool. If a thermoplastic production tool is used, care should be taken not to generate too much heat, as this can deform the thermoplastic production tool, thereby limiting its lifespan. More information on the design and manufacture of production molds or master tools can be found in U.S. Patent Nos. 5,152,917 (Pieper et al.); 5,435,816 (Spurgeon et al.); 5,672,097 (Hoopman et al.); 5,946,991 (Hoopman et al.); 5,975,987 (Hoopman et al.); and 6,129,540 (Hoopman et al.).

[0052] The cavity can be accessed from either the top or bottom surface of the mold. In some cases, the cavity can extend through the entire thickness of the mold. Alternatively, the cavity can extend only a portion of the thickness of the mold. In one embodiment, the top surface is generally parallel to the bottom surface of the mold, wherein the mold cavity has a generally uniform depth. At least one edge of the mold, i.e., the edge in which the cavity is formed, can remain exposed to the ambient atmosphere during the step in which the volatile components are removed.

[0053] The cavities have a specific three-dimensional shape to produce shaped ceramic abrasive particles. The depth dimension is equal to the vertical distance from the top surface to the lowest point on the bottom surface. The depth of a given cavity can be uniform or can vary along its length and / or width. The cavities of a given mold can have the same shape or different shapes.

[0054] The third process step involves filling the cavity in the mold with the ceramic precursor dispersion (e.g., by conventional techniques). In some embodiments, a knife-roll coater or a vacuum slot die coater may be used. If desired, a release agent may be used to aid in the removal of the particles from the mold. Typical release agents include oils (such as peanut oil or mineral oil, fish oil), silicones, polytetrafluoroethylene, zinc stearate, and graphite. Generally, a release agent such as peanut oil in a liquid such as water or alcohol is applied to the surface of the production tool in contact with the ceramic precursor dispersion such that when demolding is desired, there is about 0.1 mg / in3 of the dispersion per unit area of ​​the mold. 2(0.02mg / cm 2 ) to about 3.0 mg / in 2 (0.5mg / cm 2 ) or about 0.1 mg / in 2 (0.02mg / cm 2 ) to approximately 5.0 mg / in 2 (0.8mg / cm 2 ). In some embodiments, the top surface of the mold is coated with a ceramic precursor dispersion. The ceramic precursor dispersion can be pumped onto the top surface.

[0055] Next, a scraper or leveling bar (i.e., a scraper) can be used to press the ceramic precursor dispersion completely into the cavity of the mold. The remaining portion of the ceramic precursor dispersion that did not enter the cavity can be removed from the top surface of the mold and recycled. In some embodiments, a small portion of the ceramic precursor dispersion may remain on the top surface, and in other embodiments, the top surface is substantially free of dispersion. The pressure applied by the scraper or leveling bar is typically less than 100 psi (0.7 MPa), less than 50 psi (0.3 MPa), or even less than 10 psi (69 kPa). In some embodiments, the exposed surface of the ceramic precursor dispersion does not substantially extend beyond the top surface.

[0056] In those embodiments where it is desired to use the exposed surfaces of the cavities to form the substantially planar faces of the shaped ceramic abrasive particles, it may be necessary to overfill the cavities (eg, using a micronozzle array) and slowly dry the ceramic precursor dispersion.

[0057] The fourth process step involves removing the volatile components to dry the dispersion. Advantageously, the volatile components are removed at a rapid evaporation rate. In some embodiments, the removal of the volatile components by evaporation is carried out at a temperature above the boiling point of the volatile components. The upper limit of the drying temperature generally depends on the material from which the mold is made. For polypropylene molds, the temperature should be below the melting point of the plastic. In one embodiment, for an aqueous dispersion having about 40% to 50% solids and a polypropylene mold, the drying temperature can be about 90°C to about 165°C, or about 105°C to about 150°C, or about 105°C to about 120°C. Higher temperatures can result in improved production speeds, but can also result in degradation of the polypropylene mold, thereby limiting its useful life as a mold.

[0058] The fifth process step involves removing the resulting shaped ceramic precursor particles from the mold cavity. The shaped ceramic precursor particles can be removed from the cavity by using the following processes on the mold, alone or in combination: gravity, vibration, ultrasonic vibration, vacuum, or pressurized air to remove the particles from the mold cavity.

[0059] The shaped ceramic precursor particles can also be dried outside of the mold. If the ceramic precursor dispersion is dried to the desired degree in the mold, this additional drying step is not necessary. However, in some cases, it may be economical to employ this additional drying step to minimize the time the ceramic precursor dispersion remains in the mold. Typically, the shaped ceramic precursor particles are dried at a temperature of 50° C. to 160° C., or 120° C. to 150° C., for 10 to 480 minutes, or 120 to 400 minutes.

[0060] The sixth process step involves calcining the shaped ceramic precursor particles. During calcination, substantially all volatile materials are removed and the various components present in the ceramic precursor dispersion are converted to metal oxides. The shaped ceramic precursor particles are generally heated to a temperature of 400°C to 800°C and maintained within this temperature range until free water and more than 90% by weight of any bound volatile materials are removed. In an optional step, it may be desirable to introduce modifying additives through an impregnation process. Water-soluble salts can be introduced into the pores of the calcined shaped ceramic precursor particles through impregnation. The shaped ceramic precursor particles are then pre-calcined again. This optional step is further described in U.S. Patent No. 5,164,348 (Wood).

[0061] The seventh process step involves sintering the calcined shaped ceramic precursor particles to form ceramic particles. Prior to sintering, the calcined shaped ceramic precursor particles are not fully densified and, therefore, lack the desired hardness for use as shaped ceramic abrasive particles. Sintering is performed by heating the calcined shaped ceramic precursor particles to a temperature of 1000° C. to 1650° C. The length of time the calcined shaped ceramic precursor particles must be exposed to the sintering temperature to achieve this degree of transformation depends on a variety of factors but is typically between 5 seconds and 48 hours.

[0062] In another embodiment, the duration of the sintering step ranges from one minute to 90 minutes.After sintering, the shaped ceramic abrasive particles can have a Vickers hardness of 10 GPa (gigapascals), 16 GPa, 18 GPa, 20 GPa, or greater.

[0063] Other steps can be used to modify the process, such as, for example, rapidly heating the material from the calcining temperature to the sintering temperature, centrifuging the ceramic precursor dispersion to remove sludge and / or waste. In addition, if desired, the method can be modified by combining two or more of these process steps. Conventional process steps that can be used to modify the process of the present disclosure are more fully described in U.S. Patent No. 4,314,827 (Leitheiser).

[0064] Shaped ceramic abrasive particles composed of crystallites of alpha alumina, magnesium aluminum spinel, and rare earth hexaaluminate can be prepared using sol-gel alpha alumina precursor particles according to the methods described in, for example, U.S. Patent No. 5,213,591 (Celikkaya et al.) and U.S. Published Patent Application Nos. 2009 / 0165394A1 (Culler et al.) and 2009 / 0169816A1 (Erickson et al.). The alpha alumina abrasive particles can include zirconium oxide, as disclosed in U.S. Patent No. 5,551,963 (Larmie). Alternatively, the alpha alumina abrasive particles can have microstructures or additives, for example, as disclosed in U.S. Patent No. 6,277,161 (Castro). More information on methods of making shaped ceramic abrasive particles is disclosed in co-pending U.S. Published Patent Application No. 2009 / 0165394A1 (Culler et al.).

[0065] Surface coatings on shaped ceramic abrasive particles can be used to improve adhesion between the shaped ceramic abrasive particles and the binder material in the abrasive article or can aid in electrostatic deposition of the shaped ceramic abrasive particles. In one embodiment, a surface coating as described in U.S. Patent No. 5,352,254 (Celikkaya) can be used in an amount of 0.1% to 2% relative to the weight of the shaped abrasive particles. Such surface coatings are described in U.S. Patent Nos. 5,213,591 (Celikkaya et al.), 5,011,508 (Wald et al.), 1,910,444 (Nicholson), 3,041,156 (Rowse et al.), 5,009,675 (Kunz et al.), 5,085,671 (Martin et al.), 4,997,461 (Markhoff-Matheny et al.), and 5,042,991 (Kunz et al.). Additionally, the surface coating can prevent the shaped abrasive particles from blocking. The term "blocking" is used to describe the phenomenon whereby metal particles from the workpiece being abraded become welded to the tops of the shaped ceramic abrasive particles. Surface coatings that perform the above functions are known to those skilled in the art.

[0066] The shaped ceramic abrasive particles of the present disclosure can generally be manufactured using tools cut from diamond dies (or dies that are inverse replicas thereof), thereby providing higher feature definition than other manufacturing alternatives, such as, for example, stamping or punching. Typically, the cavities in the tool surface have smooth surfaces that converge along sharp edges, but this is not required. The resulting shaped ceramic abrasive particles have a corresponding nominal average shape that corresponds to the shape of the cavities in the tool surface; however, variations from the nominal average shape (e.g., random variations) can occur during manufacturing, and shaped ceramic abrasive particles exhibiting such variations are included within the definition of shaped ceramic abrasive particles as used herein.

[0067] 2A-2D illustrate different shaped abrasive particles that can be used to form abrasive articles. Figure 2A-1 and Figure 2A-2 A triangular shaped abrasive particle 200 is shown having a side length 210 and a thickness 215. The particle 200 was made using a mold having an aspect ratio of 4:1 (e.g., the side length of the mold producing side length 210 is four times the thickness of the mold producing thickness 215) and, once fully fired, had approximately 69 particles per die. Figure 2B-1 and Figure 2B-2 A triangular shaped abrasive particle 220 is shown having a side length 230 and a thickness 235. The particle 220 was made using a mold having an aspect ratio of 3:1 (the side length of the mold that produced the side length 230 was three times the thickness of the mold that produced the thickness 235), and once fully fired, there were approximately 55 particles per die. However, it is noted that the final aspect ratio of the fired particles varies due to the manufacturing process, as shown in Table 1 below. Figure 2D-1 and Figure 2D-2 A triangular shaped abrasive particle 270 is shown having a side length 275 and a thickness 280. The particle 270 was made using a mold having an aspect ratio of 5:1 (the side length of the mold producing side length 270 is five times the thickness of the mold producing thickness 280) and once fully fired, there were approximately 88 particles per die.

[0068] Figure 2C-1 and Figure 2C-2 A particle 250 is shown having three sides, each side having a concave curvature. Figure 2C-2 As shown, the concave curvature of each side 255 can cause some shrinkage to produce curvature 262 along the edge as a result of the particle drying process. - Particles 250 are manufactured using a mold with an aspect ratio of 7:2 (where side length 255 is 3.5 times the length of thickness 260), and once fully fired, each die has approximately 87 particles.

[0069] Table 1 below shows some exemplary parameter ranges for particles 200 , 220 , 250 , and 270 .

[0070] Table 1

[0071]

[0072] As shown in Table 1, in embodiments herein, the aspect ratio of the fired particles may be in the range of 3: 1 to 7: 1, or in some embodiments, in the range of 3: 1 to 6: 1. In some further embodiments, the aspect ratio of the particles described in the embodiments herein may be in the range of 3.5: 1 to 5.5: 1. Figure 3 Methods of forming abrasive articles according to embodiments herein are shown.

[0073] Shaped ceramic abrasive particles can be used, for example, to construct abrasive articles, including, for example, coated abrasive articles (e.g., conventional make- and size-coated abrasive articles, slurry-coated abrasive articles, and structured abrasive articles). Generally, abrasive articles comprise a plurality of abrasive particles retained in a binder. Figure 3 A method of making a coated abrasive article according to embodiments described herein is shown. Method 300 can be used, for example, to make any of the coated abrasive articles discussed herein. However, it can also be used to make other suitable coated abrasive articles.

[0074] In frame 310, a backing is provided. In some embodiments, the backing can be pretreated before the coating process. For example, pretreatment can help increase adhesion, reduce abrasive weight loss or reduce static electricity. In other embodiments, the backing provided can also be untreated. The backing can also have other features, such as perforations, laminated layers, etc. The backing can be flexible or rigid and can be made of any suitable woven or non-woven material. Some embodiments herein relate to a backing for abrasive belts, which are typically coated abrasive discs. However, it is clearly envisioned that the particles described herein can provide similar beneficial effects in other abrasive products such as coated abrasive discs, non-woven fiber discs, abrasive pads, etc.

[0075] In block 320, a make coat is provided. The make coat is typically provided in an uncured form so that the deposited abrasive particles can be embedded. The make coat can be deposited on the backing in any number of suitable ways, including, for example, spraying, rolling, knife coating, and the like.

[0076] In block 330, abrasive grains are embedded in the make coat. As described herein, for comparative purposes, abrasive grains 200, 220, and 250 are all used to make the abrasive articles described herein in the Examples. However, it is expressly contemplated that other shapes may be used. The abrasive articles are embedded with a coat weight 336, which refers to the average number of grains on the abrasive article, typically expressed as grains per square inch.

[0077] The inventors have surprisingly observed that abrasive belts made with abrasive grains 250 at a coating weight exceeding 400 grains per square inch exhibit good abrading behavior over a wide range of pressures. Generally, one would expect high coating weights to perform well in high-pressure applications, but not at medium or low pressures. However, abrasive belts made with abrasive grains 250 at a high coating weight exhibited better-than-expected cut rates over a wide range of applied pressures.

[0078] Additionally, note that the high coat weight tapes made with abrasive grains 250 exhibited high peak counts (correct orientation), high cut rates, and low abrasive weight loss. Balancing all three of these parameters is difficult.

[0079] It was also surprising to find that the same particles also showed higher cut rates and lower abrasive weight loss than expected when used at low coat weights. Generally speaking, lower coat weight applications would not be expected to perform well at high pressures because the particles would break down too quickly.

[0080] The first set of abrasive particles can be deposited and oriented on the backing using any suitable method, such as using electrostatic alignment, which will orient the particles in the XY directions, but not in the Z direction. Alternatively, in embodiments where the abrasive particles include a magnetically responsive element or coating, the first set of abrasive particles can be deposited and oriented using magnetic alignment, such that the particles will be oriented in a desired orientation when exposed to a magnetic field.

[0081] Orienting may include orienting the abrasive particles so that corresponding faces of adjacent particles are parallel to each other, as indicated in block 332, and so that sharp tips or edges face away from the backing, as indicated in block 334. Alignment of the abrasive particles may be accomplished using electrostatic or magnetic coatings, as described in PCT Patent Application Publication Nos. WO 2018 / 080703 (Nelson et al.), WO 2018 / 080756 (Eckel et al.), WO 2018 / 080704 (Eckel et al.), WO 2018 / 080705 (Adefris et al.), WO 2018 / 080765 (Nelson et al.), WO 2018 / 080784 (Eckel et al.), WO 2018 / 136271 (Eckel et al.), WO 2018 / 134732 (Nienaber et al.), WO 2018 / 080755 (Martris et al.), and WO 2018 / 080766 (Nelson et al.). inez et al.), WO2018 / 080799 (Nienaber et al.), WO2018 / 136269 (Nienaber et al.), WO2018 / 136268 (Jesme et al.), WO2019 / 207415 (Nienaber et al.), WO2019 / 207417 (Eckel et al.), WO2019 / 207416 (Nienaber et al.), and U.S. Provisional Application 62 / 914,778 filed October 14, 2019, U.S. Provisional Application 62 / 875,700 filed July 18, 2019, and U.S. Provisional Application 62 / 924,956 filed October 23, 2019.

[0082] Rendering the particles magnetically responsive may include coating non-magnetically responsive particles with a magnetically responsive coating. However, in other embodiments, the particles are formed of a magnetically responsive material, for example, as described in co-owned provisional patent US62 / 914778, filed October 14, 2019. At least one magnetic material may be contained within or coated onto the shaped abrasive particles. Examples of magnetic materials include iron; cobalt; nickel; various alloys of nickel and iron sold as various grades of Permalloy; and various grades of Fernico, Kovar, Fernico I, or Fernico II. II); various alloys of iron, aluminum, nickel, cobalt, and sometimes copper and / or titanium, sold as various grades of Alnico; alloys of iron, silicon, and aluminum (about 85:9:6 by weight), sold as FeAlSi; Heusler alloys (e.g., Cu2MnSn); manganese bismuthides (also known as Bismanol); rare earth magnetite

[0015] Magnetized materials include gadolinium, dysprosium, holmium, europium oxide, neodymium, alloys of iron and boron (e.g., Nd2Fe14B), and alloys of samarium and cobalt (e.g., SmCo5); MnSb; MnOFe2O3; Y3Fe5O12; CrO2; MnAs; ferrites, such as ferrite, magnetite; zinc ferrite; nickel ferrite; cobalt ferrite, magnesium ferrite, barium ferrite, and strontium ferrite; yttrium iron garnet; and combinations thereof. In some embodiments, the magnetizable material is an alloy containing 8 to 12 weight percent aluminum, 15 to 26 weight percent nickel, 5 to 24 weight percent cobalt, up to 6 weight percent copper, and up to 1 weight percent titanium, with the remainder of the material totaling 100 weight percent being iron. In some other embodiments, a magnetizable coating can be deposited on the abrasive particles 100 using vapor deposition techniques such as, for example, physical vapor deposition (PVD), including magnetron sputtering. The inclusion of these magnetizable materials can allow the shaped abrasive particles to respond to a magnetic field. Any of the shaped abrasive particles can comprise the same material or different materials.

[0083] The magnetic coating can be a continuous coating, for example, which coats the entire abrasive particle, or at least an entire surface of the abrasive particle. In another embodiment, a continuous coating is a coating in which there are no uncoated portions on the coated surface. In one embodiment, the coating is an integral coating formed from a single layer of magnetic material, rather than as discrete magnetic particles. In one embodiment, the magnetic coating is provided on the abrasive particle while the abrasive particle is still in the mold cavity, such that the magnetic coating is in direct contact with the surface of the abrasive particle precursor. In one embodiment, the thickness of the magnetic coating is at most equal to or preferably less than the thickness of the abrasive particle. In one embodiment, the magnetic coating does not exceed about 20% by weight of the final particle, or does not exceed about 10% by weight of the final particle, or does not exceed 5% by weight of the final particle.

[0084] It generally takes two steps to magnetically align abrasive particles relative to each other. First, magnetizable abrasive particles as described herein are provided on a substrate having a major surface. Second, a magnetic field is applied to the magnetizable abrasive particles so that most of the magnetizable abrasive particles are oriented to be roughly perpendicular to the major surface. Without applying a magnetic field, the resulting magnetizable abrasive particles may not have a magnetic moment, and the constituent abrasive particles or magnetizable abrasive particles may be randomly oriented. However, when a sufficient magnetic field is applied, the magnetizable abrasive particles will tend to align with the magnetic field. In an advantageous embodiment, the ceramic particles have a major axis (e.g., an aspect ratio of 2) and the major axis is aligned parallel to the magnetic field. Preferably, most or even all of the magnetizable abrasive particles will have magnetic moments that are roughly aligned parallel to each other. As described above, the abrasive particles as described herein may have more than one magnetic moment and will be aligned with the net magnetic moment.

[0085] The magnetic field can be provided by any external magnet (e.g., a permanent magnet or an electromagnet) or a magnet group. In some embodiments, the magnetic field is typically in the range of 0.5 to 1.5 kOe. Preferably, the magnetic field is substantially uniform over the scale of a single magnetizable abrasive particle.

[0086] For the production of abrasive articles, a magnetic field can optionally be used to position and / or orient the magnetizable abrasive particles prior to curing a binder (e.g., glassy or organic) precursor to produce the abrasive article. The magnetic field can be substantially uniform across the magnetizable abrasive particles before the particles are fixed in place in the binder or continuous throughout the binder, or the magnetic field can be non-uniform, or even effectively separated into discrete portions. Typically, the orientation of the magnetic field is configured to achieve alignment of the magnetizable abrasive particles according to a predetermined orientation, such as to align the particles parallel to each other and with cut surfaces oriented in the downweb direction.

[0087] Examples of magnetic field configurations and apparatus for generating magnetic fields are described in U.S. Pat. No. 8,262,758 (Gao) and U.S. Pat. Nos. 2,370,636 (Carlton), 2,857,879 (Johnson), 3,625,666 (James), 4,008,055 (Phaal), 5,181,939 (Neff) and UK Patent No. 1 477 767 (Edenville Engineering Works Limited).

[0088] As shown in blocks 332 and 335, orientation can also be achieved using patterned dispensing. In some embodiments, patterned dispensing can be achieved using an alignment tool by a method similar to that described in PCT Patent Application Publication Nos. 2016 / 205133 (Wilson et al.), 2016 / 205267 (Wilson et al.), 2017 / 007703 (Wilson et al.), and 2017 / 007714 (Liu et al.). The method generally involves the following steps: filling each cavity in a production tool with one or more triangular abrasive particles (typically one or two); aligning the filled production tool and the make layer precursor-coated backing to transfer the triangular abrasive particles to the make layer precursor; transferring the abrasive particles from the cavity to the make layer precursor-coated backing; and removing the production tool from the aligned position. The make coat precursor is then at least partially cured (typically to a degree sufficient to securely adhere the triangular abrasive particles to the backing), and a size coat precursor is then applied to the make coat precursor and abrasive particles, and the size coat precursor is at least partially cured to provide a coated abrasive tape. The process can be batch or continuous and can be performed manually or automatically, for example, using robotic equipment. Not all steps must be performed or performed continuously, but the steps can be performed in the order listed or with additional steps performed between each step. The triangular abrasive particles can be placed in a desired Z-axis rotational orientation by first placing the triangular abrasive particles in appropriately shaped cavities in a dispensing surface of a production tool that is arranged in a complementary rectangular grid pattern, or other suitable pattern based on the shape of the abrasive particles.

[0089] Transfer coating using a tool with a patterned cavity can be similar to the transfer coating described in U.S. Patent Application Publication No. 2016 / 0311081A1 (Culler et al.). In some embodiments, the abrasive particles can be applied to the make layer through a patterned mesh or screen.

[0090] The abrasive particles may also have other features 338 .

[0091] Examples of suitable abrasive grains include: fused alumina; heat-treated alumina; white fused alumina; ceramic alumina materials, such as those commercially available from 3M Company, St. Paul, MN under the trade name 3M CERAMIC ABRASIVE GRAIN; brown alumina; blue alumina; silicon carbide (including green silicon carbide); titanium diboride; boron carbide; tungsten carbide; garnet; titanium carbide; diamond; cubic boron nitride; garnet; fused alumina-zirconia; iron oxide; chromium oxide; zirconium oxide; titanium dioxide; tin oxide; quartz; feldspar; flint; corundum; sol-gel abrasive grains; and combinations thereof. Of these materials, molded sol-gel alpha alumina abrasive grains are preferred in many embodiments. Abrasive materials that cannot be processed by sol-gel methods can be molded with a temporary or permanent binder to form shaped precursor particles, which are then sintered to form abrasive particles, for example, as disclosed in U.S. Patent Application Publication No. 2016 / 0068729A1 (Erickson et al.).

[0092] Examples of sol-gel abrasive particles and methods of making the same can be found in U.S. Pat. Nos. 4,314,827 (Leitheiser et al.), 4,623,364 (Cottringer et al.), 4,744,802 (Schwabel), 4,770,671 (Monroe et al.), and 4,881,951 (Monroe et al.). It is also contemplated that the abrasive particles may comprise abrasive agglomerates, such as those described in, for example, U.S. Pat. Nos. 4,652,275 (Bloecher et al.) or 4,799,939 (Bloecher et al.). In some embodiments, the first and / or abrasive particles may be surface treated with a coupling agent (e.g., an organosilane coupling agent) or subjected to other physical treatments (e.g., iron oxide or titanium oxide) to enhance adhesion of the abrasive particles to the binder (e.g., make coat and / or size coat). The abrasive grains may be treated before they are combined with the corresponding binder precursor, or they may be surface treated in situ by including a coupling agent into the binder.

[0093] Preferably, the abrasive particles are ceramic abrasive particles, such as, for example, polycrystalline alpha alumina particles produced by a sol-gel process. Abrasive particles composed of microcrystals of alpha alumina, magnesium aluminum spinel, and rare earth hexaaluminates can be prepared using sol-gel precursor alpha alumina particles according to the methods described in, for example, U.S. Patent No. 5,213,591 (Celikkaya et al.) and U.S. Patent Application Publication Nos. 2009 / 0165394A1 (Culler et al.) and 2009 / 0169816A1 (Erickson et al.).

[0094] Shaped abrasive particles based on alpha alumina can be made according to a well-known multi-step process. Briefly, the method includes the steps of making a seeded or unseeded sol-gel alpha alumina precursor dispersion that can be converted to alpha alumina; filling one or more mold cavities with the desired shaped abrasive particles with the sol-gel, drying the sol-gel to form precursor triangular abrasive particles; removing the precursor abrasive particles from the mold cavities; calcining the precursor abrasive particles to form calcined precursor abrasive particles, and then sintering the calcined precursor abrasive particles to form a first set of abrasive particles and / or a second set of abrasive particles. The process will now be described in more detail.

[0095] More details regarding methods of making sol-gel prepared abrasive particles can be found, for example, in U.S. Patent Nos. 4,314,827 (Leitheiser); 5,152,917 (Pieper et al.); 5,435,816 (Spurgeon et al.); 5,672,097 (Hoopman et al.); 5,946,991 (Hoopman et al.); 5,975,987 (Hoopman et al.); and 6,129,540 (Hoopman et al.); and in U.S. Published Patent Application No. 2009 / 0165394 Al (Culler et al.).

[0096] Examples of slurry-made alpha alumina abrasive particles can be found in WO 2014 / 070468, published on May 8, 2014. Slurry-made particles can be formed from a powder precursor, such as alumina powder. Slurry processing can be advantageous for larger particles that are difficult to make using sol-gel techniques.

[0097] The abrasive grains may undergo a sintering process, such as, for example, the process described in U.S. Patent 10,400,146, issued on September 3, 2019. However, other processing techniques are expressly contemplated.

[0098] Ultrafine grain shape grains can be formed using the techniques described in USPAP 2019 / 0233693 published on August 1, 2019, or WO 2018023177 published on December 20, 2018, or WO 2018 / 207145 published on November 15, 2018.

[0099] Softer shaped grain particles with a Mohs hardness between 2.0 and 5.0, which can be used for scratch-free applications, can be produced according to the method described in WO 2019 / 215539 published on November 14, 2019.

[0100] In some preferred embodiments, the abrasive particles are precisely shaped, and an individual abrasive particle will have a shape that is substantially the shape of a portion of the cavity of a mold or production tool in which the particle precursor is dried prior to optional calcining and sintering.

[0101] Abrasive particles used in the present disclosure can generally be manufactured using a tool (ie, a mold) and cut using precision machining, providing greater feature definition than other manufacturing alternatives such as, for example, stamping or punching.

[0102] The shaped abrasive particles may have at least one sidewall, which may be a sloping sidewall. In some embodiments, there may be more than one (e.g., two or three) sloping sidewalls, and the inclination or angle of each sloping sidewall may be the same or different. In other embodiments, the sidewall may be minimized for particles in which the first and second faces taper to a thin edge or point where they meet without a sidewall. The sloping sidewall may also be defined by a radius R (e.g., as in U.S. Patent Application No. 2010 / 0151196). Figure 5B ). The radius R of each of the side walls may vary.

[0103] Specific examples of shaped particles having ridges include roof-shaped particles, such as those described in WO 2011 / 068714. Figure 4 A to Figure 4 The particles shown in C. Preferred roof-shaped particles include particles having a hip roof or a hip roof shape (a type of roof in which any side wall facets present slope downwardly from a ridgeline to a first side). A hip roof generally does not include vertical side walls or facets.

[0104] Methods for making shaped abrasive particles having at least one sloped sidewall are described, for example, in US Patent Application Publication No. 2009 / 0165394.

[0105] The shaped abrasive particles may also include a plurality of ridges on their surface. A plurality of grooves (or ridges) may be formed by a plurality of ridges (or grooves) in the bottom surface of the mold cavity, which have been found to make it easier to remove the shaped abrasive particle precursors from the mold.

[0106] A plurality of grooves (or ridges) are not specifically limited and can, for example, comprise parallel lines which may extend completely or incompletely through the side. Preferably, the parallel lines intersect with the periphery at a 90 ° angle along the first edge. The cross-sectional geometry of the grooves or ridges can be a truncated triangle, a triangle or other geometric shapes, as further discussed below. In various embodiments of the present invention, the depth of a plurality of grooves can be between approximately 1 micron and approximately 400 microns.

[0107] In another embodiment, a plurality of grooves include a crosshatch pattern of intersecting parallel lines, which may extend completely or incompletely through the face. In various embodiments, the crosshatch pattern may include parallel lines or non-parallel lines, various lines intersecting with a percentage spacing, an arcuate cross line, or various cross-sectional geometries of grooves. In other embodiments, the quantity of the ridges (or grooves) in the bottom surface of each mold cavity may be between 1 and approximately 100, or between 2 and approximately 50, or between approximately 4 and approximately 25, thereby forming a corresponding number of grooves (or ridges) in the shaped abrasive grain.

[0108] Methods for making shaped abrasive particles having grooves on at least one side are described, for example, in US Patent Application Publication No. 2010 / 0146867.

[0109] The shaped abrasive particles may also have one or more recesses on one of the faces of the abrasive particles, as described in PCT application serial number IB2019 / 060861, filed December 16, 2019.

[0110] The shaped abrasive particles can have openings (preferably openings extending through or across the first side and the second side). Methods for making shaped abrasive particles having openings are described, for example, in US Patent Application Publication Nos. 2010 / 0151201 and 2009 / 0165394.

[0111] The shaped abrasive particles may also have at least one recessed (or concave) face or facet; at least one face or facet that is shaped outwardly (or convex). Methods for making dish-shaped abrasive particles are described, for example, in U.S. Patent Application Publication Nos. 2010 / 0151195 and 2009 / 0165394. Additionally, the shaped abrasive particles may also have a multi-faceted surface, as described in U.S. Patent No. 10,150,900, published on December 11, 2018.

[0112] The shaped abrasive particles can also have at least one fractured surface.Methods for making shaped abrasive particles having at least one fractured surface are described, for example, in US Patent Application Publication Nos. 2009 / 0169816 and 2009 / 0165394.

[0113] The shaped abrasive particles may also have cavities.The shaped abrasive particles may also include pores, such as described in US Patent No. 8,142,532, issued March 27, 2012, which is incorporated herein by reference.

[0114] The shaped abrasive particles can also have a low roundness coefficient.Methods for making shaped abrasive particles having a low roundness coefficient are described, for example, in US Patent Application Publication No. 2010 / 0319269.

[0115] The shaped abrasive particles can have a second vertex on the second side, as described in U.S. 9,447,311, published on September 16, 2016. Methods for making abrasive particles in which the second side is a vertex (e.g., a double-wedge-shaped abrasive particle) or a ridge line (e.g., a roof-shaped particle) are described, for example, in U.S. Provisional Application 2012 / 022733, published on September 13, 2012.

[0116] The shaped abrasive particles can be formed to have sharp tips, such as those described in U.S. Provisional Application 2019 / 0233693, published on August 1, 2019, or U.S. Provisional Application Serial No. 62 / 877443, filed on July 23, 2019.

[0117] The shaped abrasive particles can also be formed to include rake angles, such as those described in WO 2019 / 207423, published on October 31, 2019, or those described in WO 2019 / 207417, published on October 31, 2019, or those described in PCT application serial number IB 2019 / 059112, filed on October 24, 2019.

[0118] Shaped abrasive particles can also be formed to have precisely shaped portions and non-shaped portions, such as crushed portions, as described in U.S. Provisional Patent Application No. 62 / 833,865, filed April 15, 2019.

[0119] The shaped abrasive particles may also have a combination of one or more of the shape features discussed herein, including sloped sidewalls, grooves, recesses, facets, fractured surfaces, cavities, more than one vertex, sharp edges, non-shaped portions, notches, rake angles, and / or a low roundness factor.

[0120] The shaped abrasive particles may have an elongated shape, such as those described in U.S. Provisional Application No. 2019 / 0106362, published on April 11, 2019, or in WO 2019 / 069157, published on April 11, 2019. The elongated shape may be triangular prism-shaped, rod-shaped, or otherwise include one or more vertices along a perimeter.

[0121] The shaped abrasive particles can have a variable cross-sectional area along the length of the particle, such as those described in U.S. Provisional Application No. 2019 / 0249051. For example, the shaped abrasive particles can be dog-bone shaped or otherwise have a cross-sectional area that varies from a first end to a second end.

[0122] The shaped abrasive particles may have a tetrahedral shape, such as those described in WO 2018 / 207145, published on November 15, 2018, or those described in U.S. Patent No. 9,573,250, issued on February 21, 2017.

[0123] The shaped abrasive particles may also have concave or convex portions, or may be defined as having one or more acute internal angles, such as those described in U.S. Patent No. 10,301,518, issued May 28, 2019.

[0124] The shaped abrasive particles may also include shape-to-shape particles, such as plate-to-plate shaped particles as described in 8,728,185, published May 20, 2014.

[0125] The shaped abrasive particles may also include shaped abrasive particles having irregular polygonal shapes, as described in U.S. Provisional Patent Application 62 / 924,956, filed on October 23, 2019.

[0126] The shaped abrasive particles can also be shaped as free-standing abrasive particles so that the cutting portion is more likely to be embedded in the make coat, for example, in an orientation away from the backing, such as those described in PCT application serial number IB 2019 / 060457 filed on December 4, 2019.

[0127] The first and / or second set of abrasive particles are typically selected to have a length ranging from 1 micron to 15,000 microns, more typically 10 microns to about 10,000 microns, and still more typically 150 microns to 2,600 microns, although other lengths may be used.

[0128] In some embodiments, abrasive grain can have the length of side of 0.1 micron to 3500 micron, more generally 50 microns to 3000 microns and more generally 100 microns to 2600 micron scopes (as described below about Fig. 5 from tip to tip measurement), but other lengths can also be used.In some embodiments discussed herein, the length of side of abrasive grain is at least 1275 microns and less than 1525 microns.In other embodiments of this paper, the length of side of abrasive grain is at least 575 microns and less than 750 microns.In other embodiments of this paper, the length of side of abrasive grain is at least 450 microns and less than 575 microns.In some embodiments, abrasive grain can have at least 2,3,4,5,6,7 or bigger aspect ratio (ratio of length to thickness).

[0129] Surface coatings on abrasive particles can be used to improve adhesion between the abrasive particles and the binder in the abrasive article, or can be used to aid in electrostatic deposition of the abrasive particles. In one embodiment, a surface coating as described in U.S. Pat. No. 5,352,254 (Celikkaya) can be used in an amount of 0.1% to 2% of the surface coating relative to the weight of the abrasive particles. Such surface coatings are described in U.S. Pat. Nos. 5,213,591 (Celikkaya et al.); 5,011,508 (Wald et al.); 1,910,444 (Nicholson); 3,041,156 (Rowse et al.); 5,009,675 (Kunz et al.); 5,085,671 (Martin et al.); 4,997,461 (Markhoff-Matheny et al.); and 5,042,991 (Kunz et al.). In addition, the surface coating can prevent the abrasive particles from blocking. "Capping" is a term that describes the phenomenon whereby metal particles from the workpiece being abraded become welded to the tops of the abrasive particles. Surface coatings that perform the above functions are known to those skilled in the art.

[0130] Once the first and second abrasive particles are embedded in the make coat precursor, it is at least partially cured to maintain the mineral orientation during application of the size coat precursor. Typically, this involves B-staging the make coat precursor, but further curing may be employed as desired. B-staging may be achieved, for example, using heat and / or light and / or a curing agent, depending on the properties of the make coat precursor selected. The make coat precursor may include, for example, glues, phenolic resins, aminoplast resins, urea-formaldehyde resins, melamine-formaldehyde resins, urethane resins, free-radically polymerizable multifunctional (meth)acrylates (e.g., aminoplast resins having pendant α,β-unsaturated groups, acrylated urethanes, acrylated epoxies, acrylated isocyanurates), epoxy resins (including bis-maleimide and fluorene-modified epoxies), isocyanurate resins, and mixtures thereof.

[0131] The basis weight of the make layer will also necessarily vary depending on the intended use, the type of abrasive grain, and the properties of the coated abrasive belt being manufactured, but will typically range from 1 gsm or 20 gsm to 200 gsm, 300 gsm, or even 400 gsm or more. The size layer precursor may be applied by any known coating method for applying size layer precursors.

[0132] In frame 340, a size coat is applied to the embedded particles. A size coat precursor is applied to the at least partially cured base coat precursor and abrasive particles. A size coat can be formed by applying a curable size coat precursor to the backing major surface. The size coat precursor can include, for example, glue, phenolic resin, aminoplast resin, urea-formaldehyde resin, melamine-formaldehyde resin, urethane resin, polyfunctional (meth) acrylate (e.g., aminoplast resin with hanging α, β-unsaturated groups, acrylated urethane, acrylated epoxy resin, acrylated isocyanurate) that can be polymerized in a free radical manner, epoxy resin (including bis-maleimide and fluorene-modified epoxy resin), isocyanurate resin, and mixtures thereof. If a phenolic resin is used to form the base coat, it is preferably also used to form the size coat. The size layer precursor can be applied by any known coating method for applying a size layer to a backing, including roll coating, extrusion die coating, curtain coating, knife coating, gravure coating, spray coating, etc. If desired, a presize layer precursor or make layer precursor according to the present invention can also be used as a size layer precursor.

[0133] The basis weight of the size layer will also necessarily vary depending on the intended use, the type of abrasive grain, and the properties of the coated abrasive belt being manufactured, but the basis weight will typically range from 1 gsm or 50 gsm to 300 gsm, 400 gsm, or even 800 gsm or more. The size layer precursor can be applied by any known coating method for coating a size layer precursor (e.g., size coat) onto a backing, including, for example, roll coating, extrusion die coating, curtain coating, and spray coating.

[0134] Once applied, the size coat precursor and the typically partially cured make coat precursor are fully cured to provide a usable coated abrasive article. Generally, this curing step involves thermal energy, but other forms of energy, such as, for example, radiation curing, may also be used. Available forms of thermal energy include, for example, thermal radiation and infrared radiation. Exemplary thermal energy sources include ovens (e.g., hanging ovens), heated rollers, hot air blowers, infrared lamps, and combinations thereof.

[0135] In addition to other components, the binder precursor (if present) in the make layer precursor and / or presize layer precursor of the coated abrasive tape according to the present disclosure may optionally contain a catalyst (e.g., a thermally activated catalyst or a photocatalyst), a free radical initiator (e.g., a thermal initiator or a photoinitiator), and a curing agent to promote curing. Such catalysts (e.g., thermally activated catalysts or photocatalysts), free radical initiators (e.g., thermal initiators or photoinitiators), and / or curing agents may be of any type known for use in coated abrasive tapes, including, for example, those described herein.

[0136] In addition to other components, the make layer precursor and the size layer precursor may also contain optional additives to, for example, modify performance and / or appearance. Exemplary additives include grinding aids, fillers, plasticizers, wetting agents, surfactants, pigments, coupling agents, fibers, lubricants, thixotropic materials, antistatic agents, suspending agents, and / or dyes.

[0137] Exemplary grinding aids can be organic or inorganic and include waxes, halogenated organic compounds, such as chlorinated waxes, such as tetrachloronaphthalene, pentachloronaphthalene, and polyvinyl chloride; halide salts, such as sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluoride, potassium chloride, magnesium chloride; and metals and their alloys, such as tin, lead, bismuth, cobalt, antimony, cadmium, iron, and titanium. Other examples of grinding aids include sulfur, organic sulfur compounds, graphite, and metal sulfides. Combinations of different grinding aids can be used.

[0138] Exemplary antistatic agents include conductive materials such as vanadium pentoxide (eg, dispersed in sulfonated polyester), wetting agents, carbon black and / or graphite in a binder.

[0139] Examples of fillers useful in the present disclosure include silicas such as quartz, glass beads, glass bubbles, and glass fibers; silicates such as talc, clay, (montmorillonite) feldspar, mica, calcium carbonate, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate; metal sulfates such as calcium sulfate, barium sulfate, sodium sulfate, sodium aluminum sulfate, aluminum sulfate; gypsum; vermiculite; wood flour; aluminum trihydrate; carbon black; alumina; titanium dioxide; cryolite; cryolite; and metal sulfites such as calcium sulfite.

[0140] In addition, in some embodiments, in frame 350, top glue coating is applied on the multi-sizing coating.Top glue coating can include filler, grinding aid, lubricant, bonding agent or suitable other materials.When existing, top glue generally includes grinding aid and / or anti-filling material.Optional top glue layer can help to stop or reduce the accumulation of grinding debris (material ground down from workpiece) between abrasive particles, and this accumulation can significantly reduce the cutting ability of coated abrasive belt.Available top glue layer generally includes grinding aid (for example, potassium tetrafluoroborate), fatty acid metal salt (for example, zinc stearate or calcium stearate), salt of phosphate ester (for example, potassium behenyl phosphate), phosphate ester, urea-formaldehyde resin, mineral oil, cross-linked silane, cross-linked organosilicon and / or fluorochemical.Useful top glue material is further described in for example U.S. Patent number 5,556,437 (Lee et al.) and U.S. Patent number 5,508,850 (Helmin). Typically, the amount of grinding aid included in the coated abrasive product is from about 50 gsm to about 700 gsm, more typically from about 80 gsm to about 500 gsm. The supersize may contain a binder, such as, for example, those used to prepare a size coat or make coat, but it need not have any binder.

[0141] Further details regarding the construction of coated abrasive articles comprising an abrasive layer secured to a backing, wherein the abrasive layer comprises abrasive grains and a make layer, a size layer, and an optional top size layer are well known and can be found, for example, in U.S. Patent Nos. 4,734,104 (Broberg); 4,737,163 (Larkey); 5,203,884 (Buchanan et al.); 5,152,917 (Pieper et al.); 5,378,251 (Culler et al.); 5,417,726 (Stout et al.); 5,436,063 (Fol 5,496,386 (Broberg et al.); 5,609,706 (Benedict et al.); 5,520,711 (Helmin); 5,954,844 (Law et al.); 5,961,674 (Gagliardi et al.); 4,751,138 (Bange et al.); 5,766,277 (DeVoe et al.); 6,077,601 (DeVoe et al.); 6,228,133 (Thurber et al.); and 5,975,988 (Christianson).

[0142] Figure 4 Shown is a cross-sectional view of an exemplary abrasive article according to an embodiment of the present invention. For example, the abrasive article 400 can be a grinding belt. The coated abrasive article 400 has a backing (substrate) 400. Abrasive particles 430 are coupled to the backing 410 by a make coat 412. The abrasive particles 430 are shown as equilateral triangles, but this is merely exemplary. It is clearly envisioned that the abrasive particles 430 can be any suitable shape. The abrasive particles 430 can be covered by a size coat 440.

[0143] Coated abrasive articles generally include a backing, abrasive grains, and at least one binder that secures the abrasive grains to the backing. The backing can be any suitable material, including cloth, polymer film, fiber, nonwoven web, paper, combinations thereof, and processed forms thereof. The backing can be sized to form a grinding belt, a coated grinding disc, a fiber disc, or other abrasive article. Suitable binders include inorganic or organic binders (including heat-curable resins and radiation-curable resins). The abrasive grains can be present in one or both layers of the coated abrasive article.

[0144] The binder material may also contain a filler or grinding aid, typically in the form of a particulate matter. Typically, the particulate material is an inorganic material. Examples of fillers that can be used in the present disclosure include metal carbonates (e.g., calcium carbonate (e.g., chalk, calcite, marl, travertine, marble, and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (e.g., quartz, glass beads, glass bubbles, and glass fibers), silicates (e.g., talc, clay, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminate, sodium silicate), metal sulfates (e.g., calcium sulfate, barium sulfate, sodium sulfate, sodium aluminum sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, carbon black, metal oxides (e.g., calcium oxide (lime), aluminum oxide, titanium dioxide), and metal sulfites (e.g., calcium sulfite).

[0145] Generally speaking, the addition of grinding aids can increase the useful life of abrasive articles. A grinding aid is a material that significantly affects the chemical and physical processes of grinding, resulting in improved performance. While not wanting to be limited by theory, it is believed that grinding aids can (a) reduce friction between the abrasive particles and the workpiece being ground; (b) prevent abrasive particles from "blocking" (i.e., preventing metal particles from welding to the top of the abrasive particles), or at least reduce the tendency of abrasive particles to block; (c) reduce the interface temperature between the abrasive particles and the workpiece; or (d) reduce grinding forces.

[0146] Grinding aids are particularly useful in coated abrasives and bonded abrasives. In coated abrasives, grinding aids are typically used in the top size coat, which is applied to the surface of the abrasive grains. However, grinding aids are sometimes added to the size coat. Typically, the amount of grinding aid incorporated into a coated abrasive is about 50 g / m². 2 Up to 300g / m 2 (Desirably, about 80 g / m 2 Up to 160g / m 2 ). In vitrified bonded abrasive articles, grinding aids are typically impregnated into the pores of the article.

[0147] The abrasive particles can be uniformly distributed within the abrasive article or concentrated within selected areas or portions of the abrasive article. For example, in a coated abrasive, there can be two layers of abrasive particles. The first layer includes abrasive particles that are not shaped ceramic abrasive particles made in accordance with the present disclosure, while the second (outermost) layer includes abrasive particles that are shaped ceramic abrasive particles made in accordance with the present disclosure. Similarly, in a bonded abrasive, the grinding wheel can have two distinct portions. The outermost portion can include abrasive particles made in accordance with the present disclosure, while the innermost layer does not include abrasive particles made in accordance with the present disclosure. Alternatively, the shaped ceramic abrasive particles made in accordance with the present disclosure can be uniformly distributed throughout the bonded abrasive article.

[0148] More details on coated abrasive articles can be found, for example, in U.S. Pat. No. 4,734,104 (Broberg), U.S. Pat. No. 4,737,163 (Larkey), U.S. Pat. No. 5,203,884 (Buchanan et al.), U.S. Pat. No. 5,152,917 (Pieper et al.), U.S. Pat. No. 5,378,251 (Culler et al.), U.S. Pat. No. 5,417,726 (Stout et al.), U.S. Pat. No. 5,436,063 (Follett et al.), U.S. Pat. No. 5,496,386 (Broberg et al.), U.S. Pat. No. 5,609,706 (Benedict et al.), U.S. Pat. No. 5,520,711 (Helmin), U.S. Pat. No. 5,954,844 (Law et al.), U.S. Pat. No. 5,961,674 (Gagliardi et al.), and U.S. Pat. No. 5,975,988 (Christianson). More details about bonded abrasive articles can be found, for example, in U.S. Pat. No. 4,543,107 (Rue), U.S. Pat. No. 4,741,743 (Narayanan et al.), U.S. Pat. No. 4,800,685 (Haynes et al.), U.S. Pat. No. 4,898,597 (Hay et al.), U.S. Pat. No. 4,997,461 (Markhoff-Matheny et al.), U.S. Pat. No. 5,037,453 (Narayanan et al.), U.S. Pat. No. 5,110,332 (Narayanan et al.), and U.S. Pat. No. 5,863,308 (Qi et al.). More details about vitreous bonded abrasives can be found, for example, in U.S. Pat. No. 4,543,107 (Rue), U.S. Pat. No. 4,898,597 (Hay et al.), U.S. Pat. No. 4,997,461 (Markhoff-Matheny et al.), U.S. Pat. No. 5,094,672 (Giles Jr. et al.), U.S. Pat. No. 5,118,326 (Sheldon et al.), U.S. Pat. No. 5,131,926 (Sheldon et al.), U.S. Pat. No. 5,203,886 (Sheldon et al.), U.S. Pat. No. 5,282,875 (Wood et al.), U.S. Pat. No. 5,738,696 (Wu et al.), and U.S. Pat. No. 5,863,308 (Qi). More details about nonwoven abrasive articles can be found, for example, in U.S. Pat. No. 2,958,593 (Hoover et al.).

[0149] The present disclosure provides a method for abrading a surface, the method comprising contacting at least one shaped ceramic abrasive particle produced according to the present disclosure with a surface of a workpiece; and moving at least one of the shaped ceramic abrasive particle or the contact surface to abrade at least a portion of the surface with the abrasive particle. Methods for abrading with shaped ceramic abrasive particles produced according to the present disclosure range from rough grinding (i.e., high pressure, high removal) to polishing (e.g., polishing medical implants with coated abrasive belts), with the latter typically performed using finer grades (e.g., ANSI 220 and finer). Shaped ceramic abrasive particles can also be used in precision grinding applications, such as grinding camshafts with vitrified bonded wheels. The size of abrasive particles used for a particular grinding application will be apparent to those skilled in the art.

[0150] Grinding with shaped ceramic abrasive particles produced according to the present disclosure can be accomplished dry or wet. For wet grinding, the introduced liquid can be provided in the form of a light mist to a full stream of water. Examples of common liquids include water, water-soluble oils, organic lubricants, and emulsions. These liquids can be used to reduce the heat associated with grinding and / or act as lubricants. The liquid may contain trace amounts of additives such as biocides and defoamers.

[0151] Shaped ceramic abrasive particles made according to the present disclosure can be used, for example, to abrade workpieces such as aluminum metal, carbon steel, mild steel, tool steel, stainless steel, hardened steel, titanium, glass, ceramics, wood, wood-like materials (e.g., plywood and particleboard), coatings, painted surfaces, organically coated surfaces, etc. The force applied during abrasion is typically in the range of about 1 kilogram to about 100 kilograms.

[0152] Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

[0153] Example

[0154] Unless otherwise indicated, all parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight.

[0155] Unit abbreviations used in the examples: gsm = grams per square meter, °C = degrees Celsius; cm = centimeter; mm = millimeter; μm = micrometer; FPM = feet per minute and kV = kilovolts.

[0156] In portions of this specification (e.g., when describing the coating weights of various components of an abrasive article), the term "grain" is used as a unit of mass, where 1 grain is equal to 0.06479891 grams. For ease of conversion of the various coating weight values ​​described herein, 1 grain / 4×6 is equal to 4.184937328 gsm.

[0157] Table 2 below reports the materials used in the examples.

[0158] Table 2

[0159]

[0160]

[0161] Table 3 :

[0162]

[0163]

[0164] Example 1: Coated abrasive sample

[0165] Preparation of Coated Abrasive Samples of Example 1 (Example 1-A-2)

[0166] Coated abrasive samples were prepared by coating a 12" wide backing PEB with MR1 using a roller coater to deliver a weight of 210 gsm (grams per square meter). Abrasive particles 250 were electrostatically coated into the make resin at a mineral weight of 546 gsm. The samples were cured at 90°C for 90 minutes and at 102°C for 1 hour. Next, the samples were size coated with SZ2 using a roller coater to a weight of 609 gsm. The samples were cured at 90°C for 60 minutes and at 1 The samples were cured at 90°C for 30 minutes, 102°C for 12 hours, and 110°C for 1 hour. The tapes were then converted to 7.62 cm x 335.28 cm for testing using Grind Test 1 and to 7.62 cm x 91.44 cm for testing using Grind Tests 2, 3, 5, and 6.

[0167] Preparation of coated abrasive samples of Examples 2 and 3

[0168] Coated abrasive samples were prepared by coating 4" wide backing PEB with MR1 using a knife coating kit to deliver a weight of 210 gsm. Abrasive grain 250 was electrostatically coated into the make resin to achieve the specified weight in gsm as shown in Table 3. The samples were cured at 90°C for 90 minutes and at 102°C for 1 hour. Next, the samples were size coated with SZ1 or SZ2 using a 3" coating roller to the specified weight in gsm as shown in Table 3. The samples were cured at 90°C for 60 minutes and at 102°C for 1 hour. Next, the samples were top size coated to the weight in gsm as shown in Table 3. Finally, the samples were cured at 90°C for 30 minutes, at 102°C for 12 hours, and at 110°C for 1 hour. The tapes were then converted to 7.62 cm x 91.44 cm for testing.

[0169] Preparation of coated abrasive samples of Example 4

[0170] Coated abrasive samples were prepared by coating 4" wide backing PEB with MR1 using a knife coating kit to deliver a weight of 210 gsm. Abrasive particles of the geometry specified in Table 9 were electrostatically coated into the make resin to achieve the specified weight in grains per 4" x 6" area, as shown in Table 9. The samples were cured at 90°C for 90 minutes and at 102°C for 1 hour. Next, the samples were size coated with SZ2 using a 3" coating roller to the specified weight in grains per 4" x 6" area, as shown in Table 9. The samples were cured at 90°C for 60 minutes and at 102°C for 1 hour. Next, the samples were top-size coated with SSZ2 to the weight in grains per 4" x 6" area, as shown in Table 9. Finally, the samples were cured at 90°C for 30 minutes, at 102°C for 12 hours, and at 110°C for 1 hour. The strips were then converted to 7.62 cm x 91.44 cm using Grinding Test 4 for testing.

[0171] Performance test

[0172] Grinding test 1

[0173] Grinding Test 1 (GT1) was conducted using a Hammond Back Stand Polishing and Buffing Machine Model #10-ROH-D-VFD, Serial #11368, obtained from Hammond RotoFinish, Kalamazoo, MI. A 35.56 cm diameter 90 Durometer contact wheel with a 1:1 sawtooth pattern having 0.95 cm x 0.95 grooves was used. The test was conducted using an abrasive belt measuring 7.62 cm x 335.28 cm. The belt was operated at 1800 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm x 1.9 cm x 60.96 cm, with the surface to be ground measuring 1.9 cm x 1.9 cm. Ten workpieces were used for each test. The weight (in grams) of each workpiece was recorded before each grinding cycle.

[0174] During each grinding cycle, an overhead table equipped with a pneumatic cylinder is used to force each workpiece into the belt. The entire test is conducted at one of three force settings: 5.54 kg (12.2 lb) (low pressure or "LP"), 10.08 kg (22.2 lb) (medium pressure or "MP"), and 13.63 kg (30 lb) (high pressure or "HP"), depending on the desired test pressure. One of the 10 workpieces is plunged into the center of the belt, removed after 8 seconds, placed in room temperature water to cool for at least 10 seconds, dried with a paper towel, and the weight loss (in grams) of the workpiece for the 8-second plunge is recorded. The remaining 9 workpieces are then ground, cooled, and weighed in the same manner until all 10 workpieces are ground. This set of 10 plunges is called a "cycle."

[0175] Ten additional cycles of insertion were then performed in the same manner. At some point, 50% of the area of ​​the workpiece's grinding surface was oxidized due to overheating, which was visually indicated by a blue discoloration. The cycle of observing discoloration was completed, so that all ten workpieces had been inserted the same number of times. At this point, the test was complete.

[0176] The result of grinding test 1 is shown in Table 4.Calculate the total cutting (GT1 total cutting) in gram by adding the weight loss data of all cycles of all 10 workpieces.Depend on the pressure selected for test, the result can be called GT1 total cutting LP, GT1 total cutting MP or GT1 total cutting HP.Calculate the initial cutting (GT1 initial cutting LP, GT1 initial cutting MP or GT1 initial cutting HP) in gram by adding the weight loss data of first 2 cycles of all 10 workpieces.Calculate the cutting rate (GT1 cutting rate LP, GT1 cutting rate MP or GT1 initial cutting HP) of each cycle by deducting the total weight loss data after first 3 cycles from the total weight loss data after first 15 cycles and dividing the result by 12.

[0177] Grinding test 2

[0178] Grinding Test 2 (GT2) was conducted on a 10.16 cm x 91.44 cm belt converted from a coated abrasive sample. A 20.3 cm diameter 70 durometer rubber (1:1 land to groove ratio) serrated contact wheel was used. The belt was run at 2750 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm x 1.9 cm x 60.96 cm, with the surface to be ground measuring 1.9 cm x 1.9 cm. The workpiece weight was recorded in grams, and the workpiece was then pressed into the center portion of the belt with a normal force varying from 4.5 kg to 6.8 kg. Each test cycle consisted of 16 seconds of grinding. The workpiece was then cooled by quenching the 1.3 cm grinding end of the workpiece in 15.5°C water for 8 seconds, followed by a continuous jet of pressurized air for 10 seconds to dry the workpiece. The workpiece was then weighed to determine the amount of material removed in grams, thereby ending the cycle. The final workpiece weight from the previous cycle was used as the initial workpiece weight for the subsequent cycle. If the final mass of the workpiece after wear weighs less than 275 grams, a new 304 stainless steel bar with dimensions of 1.9 cm x 1.9 cm x 60.96 cm is weighed and used for the subsequent cycles. The test is terminated after 40 cycles. The initial cut in grams (GT2 initial cut) is defined as the total amount cut after 2 cycles. The cutting rate in grams (GT2 cut rate) is defined as the total amount cut after 10 cycles minus the total amount cut after 3 cycles, divided by 7. The total cut in grams (GT2 total cut) is defined as the total amount cut after 40 cycles.

[0179] Grinding test 3

[0180] Grinding Test 3 (GT3) was conducted on a 10.16 cm x 91.44 cm belt converted from a coated abrasive sample. A 20.3 cm diameter 70 durometer rubber (1:1 land to groove ratio) serrated contact wheel was used. The belt was operated at 2750 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm x 1.9 cm x 60.96 cm, with the surface to be ground measuring 1.9 cm x 1.9 cm. The workpiece weight was recorded in grams, and the workpiece was then pressed into the center portion of the belt with a normal force varying from 6.8 kg to 11.3 kg. Each test cycle consisted of 16 seconds of grinding. The workpiece was then cooled by quenching the 1.3 cm grinding end of the workpiece in 15.5°C water for 8 seconds, followed by a continuous jet of pressurized air for 10 seconds to dry the workpiece. The workpiece was then weighed to determine the amount of material removed in grams, thereby ending the cycle. The final workpiece weight from the previous cycle was used as the initial workpiece weight for the subsequent cycle. If the final mass of the workpiece after wear weighs less than 275 grams, a new 304 stainless steel bar with dimensions of 1.9 cm x 1.9 cm x 60.96 cm is weighed and used for the subsequent cycles. The test is terminated after 40 cycles. The initial cut in grams (GT3 initial cut) is defined as the total amount cut after 2 cycles. The cutting rate in grams (GT3 cutting rate) is defined as the total amount cut after 10 cycles minus the total amount cut after 3 cycles, divided by 7. The total cut in grams (GT3 total cut) is defined as the total amount cut after 40 cycles.

[0181] Grinding test 4

[0182] Grinding Test 4 (GT4) was conducted on a 10.16 cm x 91.44 cm belt converted from a coated abrasive sample. A 20.3 cm diameter 70 durometer rubber (1:1 land to groove ratio) serrated contact wheel was used. The belt was operated at 2750 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm x 1.9 cm x 60.96 cm, with the surface to be ground measuring 1.9 cm x 1.9 cm. The workpiece weight was recorded in grams, and the workpiece was then pressed into the center portion of the belt. The test was conducted at one of three force settings: 5.9 kg (13 lb) (low pressure or "LP"), 8.62 kg (19 lb) (medium pressure or "MP"), and 11.34 kg (25 lb) (high pressure or "HP"), depending on the desired test pressure. Each test cycle consisted of 6 seconds of grinding. The workpiece is then cooled by quenching the 1.3 cm grinding end of the workpiece in 15.5°C water for 8 seconds, followed by a continuous jet of pressurized air for 10 seconds to dry the workpiece. The workpiece is then weighed to determine the amount of material removed in grams, thereby ending the cycle. The final workpiece weight from the previous cycle is used as the initial workpiece weight for the subsequent cycle. If the final mass of the workpiece after wear weighs less than 275 grams, a new 304 stainless steel rod with dimensions of 1.9 cm × 1.9 cm × 60.96 cm is weighed and used for the subsequent cycle. The test ends after 120 cycles. The initial cut (GT4 initial cut) in grams is defined as the total amount cut after 5 cycles. The cutting rate (GT4 cutting rate) in grams is defined as the total amount cut after 40 cycles minus the total amount cut after 8 cycles, divided by thirty-two. The total cut (GT4 total cut) in grams is defined as the total amount cut after 120 cycles. Depending on the pressure selected, the result may be referred to as GT4 Initial Cut LP, GT4 Initial Cut MP, GT4 Initial Cut HP, GT4 Cut Rate LP, GT4 Cut Rate MP, GT4 Cut Rate HP, GT4 Total Cut LP, GT4 Total Cut MP or GT4 Total Cut HP.

[0183] Grinding test 5

[0184] Grinding Test 5 (GT5) was conducted on a 10.16 cm x 91.44 cm belt converted from a coated abrasive sample. A 20.3 cm diameter 70 durometer rubber (1:1 land to groove ratio) serrated contact wheel was used. The belt was operated at 2750 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm x 1.9 cm x 60.96 cm, with the surface to be ground measuring 1.9 cm x 1.9 cm. The workpiece weight was recorded in grams, and the workpiece was then pressed into the center portion of the belt with a normal force varying from 3.2 kg to 4.5 kg. Each test cycle consisted of 16 seconds of grinding. The workpiece was then cooled by quenching the 1.3 cm grinding end of the workpiece in 15.5°C water for 8 seconds, followed by a continuous jet of pressurized air for 10 seconds to dry the workpiece. The workpiece was then weighed to determine the amount of material removed in grams, thereby ending the cycle. The final workpiece weight from the previous cycle was used as the initial workpiece weight for the subsequent cycle. If the final mass of the workpiece after wear weighs less than 275 grams, a new 304 stainless steel bar with dimensions of 1.9 cm x 1.9 cm x 60.96 cm is weighed and used for the subsequent cycles. The test ends after 30 cycles. The initial cut in grams (GT5 initial cut) is defined as the total amount cut after 2 cycles. The cutting rate in grams (GT5 cut rate) is defined as the total amount cut after 10 cycles minus the total amount cut after 3 cycles, divided by 7. The total cut in grams (GT5 total cut) is defined as the total amount cut after 30 cycles.

[0185] Grinding test 6

[0186] Grinding Test 6 (GT6) was conducted on a 10.16 cm × 91.44 cm belt converted from a coated abrasive sample. A 20.3 cm diameter 70 durometer rubber (1:1 land to groove ratio) serrated contact wheel was used. The belt was run at 2750 rpm. The workpiece was a 304 stainless steel bar measuring 1.9 cm × 1.9 cm × 60.96 cm, with the surface to be ground measuring 1.9 cm × 1.9 cm. The workpiece weight was recorded in grams, and the workpiece was then pressed into the center portion of the belt with a normal force of 2.3 kg. Each test cycle consisted of 16 seconds of grinding. The workpiece was then cooled by quenching the 1.3 cm grinding end of the workpiece in 15.5°C water for 8 seconds, followed by a continuous jet of pressurized air for 10 seconds to dry the workpiece. The workpiece was then weighed to determine the amount of material removed in grams, thereby ending the cycle. The final workpiece weight from the previous cycle was used as the initial workpiece weight for the subsequent cycle. If the final mass of the workpiece after wear weighs less than 275 grams, a new 304 stainless steel bar with dimensions of 1.9 cm x 1.9 cm x 60.96 cm is weighed and used for the subsequent cycle. The test ends after 30 cycles. The initial cut in grams (GT6 initial cut) is defined as the total amount cut after 2 cycles. The cutting rate in grams (GT6 cutting rate) is defined as the total amount cut after 10 cycles minus the total amount cut after 3 cycles, divided by 7. The total cut in grams (GT6 total cut) is defined as the total amount cut after 30 cycles.

[0187] Table 4 Figure 7 Shown in.

[0188] Table 5 Figure 8 Shown in.

[0189] Table 6 :

[0190]

[0191] Table 7 :

[0192]

[0193] Example 4

[0194] A number of ribbons were produced according to the configurations shown below in Table 8. The mineral geometries refer to the configurations discussed with respect to Figures 2A-2D.

[0195] Table 8 :

[0196]

[0197]

[0198]

[0199] Figures 9 to 11 The experimental results obtained using GT4 in some embodiments in Table 8 are shown. Using some example configurations in Table 9 and some commercial configurations, at low pressure ( Figure 9 ), medium pressure ( Figure 10 ) and high pressure ( Figure 11 ) to try some. Note that Figures 9 to 11 The "lot numbers" shown in the are non-consecutive. This is because more samples were made for testing than were actually tested, and the resulting tapes with a coat weight closest to the target coat weight and without obvious defects were selected for testing.

Claims

1. An abrasive product, comprising: backing; a primer coating applied to the backing; a plurality of shaped abrasive particles embedded in the make coat; wherein the plurality of shaped abrasive particles has a coating weight greater than 300 particles per square inch; and wherein according to Grinding Test 1, the abrasive article exhibits a GT1 Total Cut LP of at least 975 grams, a GT1 Total Cut MP of at least 4250 grams, and a GT1 Total Cut HP of at least 5075 grams when used to abrade a substrate. 2 . The abrasive article of claim 1 , wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 50 μm and less than 3000 μm. 3 . The abrasive article of claim 1 , wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 200 μm and less than 2900 μm.

4. The abrasive article of any one of claims 1 to 3, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 1275 μm and less than 1525 μm.

5. The abrasive article of any one of claims 1 to 4, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 575 μm and less than 750 μm.

6. The abrasive article of any one of claims 1 to 5, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has an aspect ratio of at least 3:1 and less than 7:

1.

7. The abrasive article of any one of claims 1 to 6, wherein the coating weight is at least 320 grains per square inch.

8. The abrasive article of any one of claims 1 to 7, wherein the coating weight is at least 400 grains per square inch.

9. The abrasive article of any one of claims 1 to 8, wherein a majority of the shaped abrasive particles are oriented with pointed ends pointing away from the backing.

10. The abrasive article according to any one of claims 1 to 9, wherein a majority of the shaped abrasive particles are oriented such that similar surfaces in a face of each of the majority of the shaped abrasive particles are oriented with respect to a grinding direction.

11. The abrasive article of any one of claims 1 to 10, wherein the abrasive article exhibits improved abrasive weight loss.

12. The abrasive article according to any one of claims 1 to 11, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: A first surface is opposite to a second surface, the first surface and the second surface being separated by a substantially constant thickness.

13. The abrasive article of claim 12, wherein the abrasive particles are dish-shaped abrasive particles.

14. The abrasive article according to any one of claims 1 to 13, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: a first surface having a perimeter including at least a first edge and a second edge, wherein a first region of the perimeter includes the second edge and extends inwardly in a concave monotonic curve and terminates at two sharp corners, thereby defining a first acute interior angle and a second acute interior angle, wherein the first acute interior angle is in the range of 35 degrees to 55 degrees, and the second acute interior angle is in the range of 35 degrees to 55 degrees, wherein the first region of the perimeter has a maximum depth that is at least 5% of the largest dimension of the shaped ceramic abrasive particles parallel to the maximum depth, and wherein the perimeter has at most four corners defining acute interior angles.

15. The abrasive article of claim 14, wherein the abrasive particles include a second surface opposite and not in contact with the first surface; and a circumferential surface disposed between and connecting the first and second surfaces, wherein the circumferential surface includes a first wall contacting the perimeter at the first edge, wherein the circumferential surface includes a second wall contacting the perimeter at the second edge, and Wherein the circumferential surface has a first predetermined shape, and wherein the circumferential surface slopes inwardly from the first surface toward the second surface.

16. The abrasive article according to any one of claims 1 to 15, wherein the abrasive article comprises an abrasive belt or abrasive disk.

17. The abrasive article of any one of claims 16, wherein the abrasive disk comprises a fiber-based backing.

18. An abrasive article, comprising: backing; a primer coating applied to the backing; a plurality of shaped abrasive particles embedded in the make coat; wherein the plurality of shaped abrasive particles has a coating weight greater than 300 particles per square inch; and wherein according to Grinding Test 4, the abrasive article exhibits a GT4 Total Cut LP of at least 390 grams, a GT4 Total Cut MP of at least 860 grams, and a GT4 Total Cut HP of at least 1300 grams when used to abrade a substrate.

19. The abrasive article of claim 18, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 50 μm and less than 3000 μm.

20. The abrasive article of claim 18 or 19, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has a side length of at least 200 μm and less than 2900 μm.

21. The abrasive article of any one of claims 18 to 20, wherein each shaped abrasive particle of the plurality of shaped abrasive particles has an aspect ratio of at least 3:1 and less than 7:

1.

22. The abrasive article of any one of claims 18 to 21, wherein the coating weight is at least 320 grains per square inch.

23. The abrasive article of any one of claims 18 to 22, wherein the coating weight is less than 520 particles.

24. The abrasive article of any one of claims 18 to 23, wherein a majority of the shaped abrasive particles are oriented with pointed ends pointing away from the backing.

25. The abrasive article of any one of claims 18 to 24, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: a first surface having a perimeter including at least a first edge and a second edge, wherein a first region of the perimeter includes the second edge and extends inwardly in a concave monotonic curve and terminates at two sharp corners, thereby defining a first acute interior angle and a second acute interior angle, wherein the first acute interior angle is in the range of 35 degrees to 55 degrees, and the second acute interior angle is in the range of 35 degrees to 55 degrees, Wherein a first region of the perimeter has a maximum depth that is at least 5% of a maximum dimension of the shaped ceramic abrasive particles parallel to the maximum depth, and wherein the perimeter has no more than four corners defining acute interior angles.

26. The abrasive article of claim 25, wherein the abrasive particles include a second surface opposite and not in contact with the first surface; and a circumferential surface disposed between and connecting the first and second surfaces, wherein the circumferential surface includes a first wall contacting the perimeter at the first edge, wherein the circumferential surface includes a second wall contacting the perimeter at the second edge, and Wherein the circumferential surface has a first predetermined shape, and wherein the circumferential surface slopes inwardly from the first surface toward the second surface.

27. The abrasive article of any one of claims 18 to 26, wherein the abrasive article exhibits improved abrasive weight loss.

28. The abrasive article of any one of claims 18 to 27, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: A first surface is opposite to a second surface, the first surface and the second surface being separated by a substantially constant thickness.

29. The abrasive article of claim 28, wherein the plurality of shaped abrasive particles are dish-shaped particles.

30. The abrasive article of any one of claims 18 to 29, wherein the abrasive article comprises an abrasive belt or abrasive disk.

31. The abrasive article of any one of claims 18 to 30, wherein the abrasive article exhibits a GT4 Total Cut LP of at least 450 when used to abrade a substrate.

32. The abrasive article of any one of claims 18 to 31, wherein the abrasive article exhibits a GT4 Total Cut MP of at least 900 when used to abrade a substrate.

33. The abrasive article of any one of claims 18 to 32, wherein the abrasive article exhibits a GT4 Total Cut HP of at least 1350 when used to abrade a substrate.

34. The abrasive article of any one of claims 18 to 33, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: a first surface having a perimeter including at least a first edge and a second edge, wherein a first region of the perimeter includes the second edge and extends inwardly in a concave monotonic curve and terminates at two sharp corners, thereby defining a first acute interior angle and a second acute interior angle, wherein the first acute interior angle is in the range of 35 degrees to 55 degrees, and the second acute interior angle is in the range of 35 degrees to 55 degrees, Wherein a first region of the perimeter has a maximum depth that is at least 5% of a maximum dimension of the shaped ceramic abrasive particles parallel to the maximum depth, and wherein the perimeter has no more than four corners defining acute interior angles.

35. A method of making an abrasive article, the method comprising: depositing a resin primer layer on the backing; Embedding a plurality of abrasive particles into the resin make layer, wherein the embedding comprises: depositing the plurality of abrasive grains; orienting the plurality of abrasive particles such that a majority of the abrasive particles are oriented with tips pointing away from a backing; and wherein the plurality of abrasive particles are deposited at a coating weight of at least 300 particles per square inch; and The resin primer layer is cured.

36. The method of claim 35, wherein the plurality of abrasive grains have an aspect ratio between 3:1 and 7:

1.

37. The method of claim 35, wherein the like surface of each abrasive in the majority of abrasives is oriented relative to a grinding direction.

38. The method of any one of claims 35 to 37, wherein the coating weight is at least 350 particles per square inch.

39. The method of any one of claims 35 to 38, wherein each abrasive particle of the plurality of abrasive particles has a first curved surface, the first curved surface being separated from a second curved surface by a thickness.

40. The abrasive article of any one of claims 35 to 39, wherein the plurality of shaped abrasive particles are shaped such that each shaped abrasive particle comprises: a first surface having a perimeter including at least a first edge and a second edge, wherein a first region of the perimeter includes the second edge and extends inwardly in a concave monotonic curve and terminates at two sharp corners, thereby defining a first acute interior angle and a second acute interior angle, wherein the first acute interior angle is in the range of 35 degrees to 55 degrees, and the second acute interior angle is in the range of 35 degrees to 55 degrees, Wherein a first region of the perimeter has a maximum depth that is at least 5% of a maximum dimension of the shaped ceramic abrasive particles parallel to the maximum depth, and wherein the perimeter has no more than four corners defining acute interior angles.

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